Safety apparatus fob regulating steam-boiler furnaces



'UNITED STATES PATENT OFFICE.

WM. G. PIKE AND ISAAC R. SCOTT, OF VVALTHAM, MASSACHUSETTS.

SAFETY APPARATUS FOR REGULATING STEAM-BOILER FURNACES.

Specification of Letters Patent No. 17,636, dated June 23, 1857.

To all whom 'it may concern:

Be it known that we, WILLIAM G. PIKE and IsAAo R. SCOTT, of Waltham, in the county of Middlesex and State of Massachusetts, have invented an Improved Safety Regulating Apparatus for Furnaces for Heating Buildings by Steam, of which the following is a full, clear, and exact description, reference being had to the annexed drawings, making part of this specification, in whichj Figure 1 is a perspective view of the furnace and boiler of a steam-heating apparatus having our improvements attached; Fig. 2, detail to be referred to hereafter.

Efforts have been made to regulate the intensity of the fire and consequently the amount of steam generated in steam heating boilers by closing the dampers of both the draft and smoke flues, by connecting them to a float in a detached chamber of water in communication with the boiler; but with such an arrangement it has not been found practicable to establish a pressure in the boiler of even a few pounds, as the height of the column of water necessary for the purpose would be inconveniently great, and in case of an excess of pressure the generation of steam will throw the water out of the boiler through the iioat chamber.

To obviate this and yet to render the boiler perfectly,` safe under a pressure sufficient for any heating purposes is the object of our present invention, which will now be more fully explained.

In the said drawings A is a casing containing a boiler of the ordinary construction, B is an o ening to the fire box. From the top of the boiler rises a pipe C that carries the steam to the radiators which heat the building, from which the water of condensation is returned to the boiler by the pipe D. The pipe E leads to the reservoir which supplies the boiler. A cock F serves to empty the boiler when necessary. a are gage cocks for testing the height of water in the boiler. As these details form no part of our present invention, they need not be further described.

G are dampers in the pipes II and I, the one being the smoke pipe, the other that which admits air for the supply of combustion. These dampers are connected together by the rod c and are weighted to open themselves.

Connected to the pipe C immediately above the boiler is a short pipe K, on the top of which is a safety valve b, and from the pipe K near its top lead the pipes L and M, the former leading from the boiler directly to the regulating apparatus, and the latter permitting a ilow of steam from the boiler onto the fire through the nozzle f whenever the safety valve b 1s raised, another pipe N connects the pipe M and consequently the nozzle f with the upper, part of the regulator, which will now be described. i

A bent pipe O is connected at one end to the pipe L and hangs outside of the boiler case A. The other end of the pipe O is open at e, where it is carried u as high as is necessary to contain a su cient column of mercury to resist the maximum pressure of steam at which the boiler is intended to be used (the mercury is seen dotted in blue in Fig. l). The o en end of the pipe O is embraced by a j acketli) of a considerably larger diameter than the pipe O. It also extends up above the open end c and is closed at to and bottom, the bottom at g embracing t e pipe O. The pipe N is connected to the jacket P near its top. The top is closed by a screw plug 7L, from which rises a standard Q, the end of which is bent over at j i. Through this bent part fi and through the plug 7i passes a rod 7c, to the lower end of which is attached a float m, which rests on the column of mercury in the pipe O. The u per end of the rod 7c` passes through a b ook n, which is secured to the rod by a screw o passing through the block. A rod l plasses horizontally through the block n and as attached to each end of it a chain p. These chains are connected to the damper G in the ipe H. The rod k may be adjusted in the lock n and be secured by the screw o. This adjustment fixes the height to which the mercury shall be raised by the pressure of the steam before the dampers G are closed by the raising of the rod c. A scale may be placed on the standard Q and an adjustable index may be attached to the rod k which will always show the pressure in the boiler. The pi e N connects the upper part of the jacket if with the pi e M.

The operation o our regulating safety apparatus is as follows: The parts being adjusted as before explained so that the dam ers will be closed when the pressure in the oiler exceeds the desired amount, the safety valve b is set to blow 0H at a definite pressure (say of 4 lbs). When this valve is raised the steam passes through the pipe M and nozzle f into the 'fire box and dampens the fire. The end e of the pipe O is carried to such a height that a pressure rather exceeding that` to which the valve b is adjusted (or say of 6 lbs.) will raise the column of mercury in it to the top of the pipe, so that if by any accident (such as adhesion to its seat) the valve b fails to operate and the pressure increases beyond the 6lbs. the mercury will be blown out of the pipe O and fall over into the bottom of the jacket P, the steam esca ing throu h the open end of the pipe O an through tie pipes N and M and nozzle f into the fire box, extinguishing the fire. This entirely recludes the possibility of an explosion, as t e pressure inthe boiler can in no instance exceed the limit to which it is fixed by the heightrof the column of mercury em loyed. The pressure may however be iixeg at a given amount within this limit (say at 3 lbs.) and be maintained with great uniformity by means of the dam ers Gr, the rod 7c being adjusted in the bloc n. So soon as the pressure increases and the column of mercury rises in the pipe O the rod 7c will through the connectlon of the chains p close the dampers G and check the instensity .of the fire, and as the ressure decreases the rod 7c will fall and the ampers will be allowed to open. When the mercury has been blown over into the jacket P by an excessive pressure, it may be drawn of by the cock S, to be again returned to the pipe .0. In lieu Vof this arrangement for recovering the mercury when blown out of the pipe VO we propose to sometimes use the device represented in Fig. 2, where the jacket P is enlarged, forming a at box R the bottom of which embraces closely the end of the pipe O, the end rising about of an inch or thereabout above the bottom of the box R. A notch is cut down in one side of the pipe as at s as low as the bottom of the box. Thus after the mercury has been blown out of the ipe O over into the box R and the steam as escaped the mercury may run back again vthrough the notch s into the pipe O without the trouble of having to replace it. This regulating apparatus thus becomes a positive and unerring safety valve, as the pressure can at no time exceed that produced by the column of mercury employed.

We do not claim regulating the intensity of furnace lires by closing the dampers in the draft and smoke pipes by means of a float within a water chamber in communication with the boiler, as we employ no such contrivance; but

What we do claim as our invention and desire to secure by Letters Patent is- The within described arrangement of the bent mercury tube D with its float and the parts immediately connected therewith, and the steam pipe f whereby the pressure Within the boiler is indicated to the eye, the dampers are regulated to suit thepressure required, and when the pressure within the boiler becomes excessive the fire is extinguished by the escaping steam, thereby forming a safety regulating apparatus, not requiring the supervision of t e attendant.

WM. G. PIKE. ISAAC R. SCOTT.

Witnesses:

ELIZABETH H. STONE, F. M. STONE. 

